Power steering systems have been designed in which the power decreases with increased speed, and these work automatically. However, under certain circumstances it is desirable manually to adjust the degree of effort required to effect steering. This is because some people are not strong enough to steer without substantial assistance, whereas others of more muscular type tend to oversteer so that the same power assistance is not required or desired by all persons.
The above difficulty is overcome in an exceedingly simple manner by interposing in the line between the hydraulic pump and the vehicle power steering mechanism a valve assembly, the valve of which can be manually adjusted to one of several positions, so that pressure fluid is passed freely therethrough or is restricted in a predetermined selective manner. In this way greater or less effort is required of the driver to steer the vehicle. After the desired adjustment of the valve is made, the valve is locked in position.